Notwithstanding the beliefs of the Catholic and Protestant churches there is no reliable and testable evidence of demonic possession occurring.

In 2008 the Texas supreme court ruled that a 17-year old girl who was imprisoned and abused while hallucinating could not sue the church over damages done during the exorcism.[3] In 2017, charges were brought against church members in the case of a North Carolina gay man who was beaten and choked for 2 hours in an exorcism attempt.[4]

According to the New Testament, Jesus cast out demons, an act which became the foundation for Christian exorcism and it appears that by the 4th Century CE there was at least one established liturgy and procedure for exorcism.[5] Those few Christians who do believe in spiritual possession feel they are empowered to do exorcisms in the name of Jesus.

Demonic or other possession was at one time used to explain everything from basic illness to odd behavior of an individual, loss of memory (for example, after an accident), social problems like alcoholism and drug abuse, prostitution, and generally any opinion which was an embarrassment to an individual, his family, or the Church. As science began to provide explanations for illness, and as society became more accepting of different points of view, "possession" became more infrequent.

Small numbers of Christians accept exorcism in the 21st century. People being exorcised appear seriously distressed; believers say the demons rather than people exorcised are distressed.[6] Of course, they said the same thing when "witches" were being tortured to extract confessions.

Michael Cuneo, a sociologist at Fordham University, says that there are 10 official Catholic exorcists in the United States, and he estimates that there are 500-600 evangelical exorcism ministries.[7][8]

“”When the Church asks publicly and authoritatively in the name of Jesus Christ that a person or object be protected against the power of the Evil One and withdrawn from his dominion, it is called exorcism. Jesus performed exorcisms and from him the Church has received the power and office of exorcising. In a simple form, exorcism is performed at the celebration of Baptism. The solemn exorcism, called "a major exorcism," can be performed only by a priest and with the permission of the bishop. The priest must proceed with prudence, strictly observing the rules established by the Church. Exorcism is directed at the expulsion of demons or to the liberation from demonic possession through the spiritual authority which Jesus entrusted to his Church. Illness, especially psychological illness, is a very different matter; treating this is the concern of medical science. Therefore, before an exorcism is performed, it is important to ascertain that one is dealing with the presence of the Evil One, and not an illness.

Baptism includes aspects of exorcism to address the horror of the infant coming into contact with its mother's icky sexual vagina. Traditional belief held that such contact caused (or allowed) an evil spirit to enter the child.[12]

The Roman Catholic Church has a body of exorcists that follow tightly regulated rules, most of which are kept secret from all but a very few church members.[13] At least one official exorcist, José Antonio Fortea, was happy to blab at least some of the rules.[14]

The Roman Catholic hierarchy is reviving interest in exorcism in hopes of reminding people that secular institutions are incapable of dealing with demons while the church, of course, can.[15] They will probably not be trying to revive interest in the 1976 killing of Anneliese Michel by two priests (Ernst Alt and Arnold Renz) via exorcism in Germany.[16]

The Eastern Orthodox Church also believes in Satan as a created being and a fallen angel with free will who always chooses to do evil.[note 1] The Devil can possess people and objects. As with Roman Catholics, priests do exorcisms and renunciation of the Devil is part of baptism. Lay Orthodox believers are also encouraged to “pray and exorcise evil.” There are specific prayers for exorcism.[18] Orthodox exorcism can involve physical restraints on the victim patient.[19]

Many Protestantfundamentalist churches are less regulated in their use of exorcism, leading to violent and occasionally deadly attempts to exorcise unwilling and/or uncomprehending victims.[20][21][22] In Texas forcible exorcism is legal or was legal in 2008.[23]

Exorcisms are needed because society is often skeptical about the teachings of the more hard-line Christian groups has lost its moral compass. According to J. F. Cogan, demonic possession is behind a wide range of happenings including gay ordination, women's ordination, and even spontaneous human combustion.[24] People can get themselves possessed by a range of activities that Christian fundamentalists dislike, such as viewing porn, illicit sex, gay sex, drug abuse, and even rock music. Astrologers and other psychics are vulnerable to demonic possession as are those who do Hindu or Buddhist meditation. Demons may time share; they torment one person then rush off at a speed slightly below the speed of light to torment someone else. Therefore possessed people may be worked up one moment and calm the next when the demon has gone off to a fresh victim.[25]

In evangelical Protestantism, exorcism is often practiced as part of a broader spiritual warfare agenda. In an even more ludicrous variety, exorcisms are performed at long distance over the telephone by Bob Larson or over the television by name it and claim it preachers ("laaay your hands on the television set").

Protestant exorcism is frequently a way televangelists make money; even teenagers do tele-exorcism. [26] Other people also make money through exorcism by selling scary books, etc. See Deliverance ministry.

In the UK exorcisms are increasing; they happen mainly in charismatic and Pentecostal churches, also among communities of West African origin. Frequently the people exorcised are psychiatrically disturbed. Psychiatrically ill people are sometimes told to stop their medication as the church believes prayer and/or exorcism is enough. If pychiatric patients do not get better after exorcism they may believe they have failed to overcome the demon and get worse.[27]

Exorcism is also practiced in other religions. In 2013, three family members in Malaysia were jailed for crushing to death a girl in an attempted Buddhist exorcism.[28] In 2014 a Belgian court charged 6 people with the death by torture of a woman in an Islamic exorcism that lasted one month.[29]

Although validity of exorcism would be a tough argument for theism, it surprisingly isn't brought up in debates very much. It could be that even the theists realize exorcism is bollocks, or it's a taboo theme among them. Or perhaps it's one of the few areas where they understand that what seems obvious to them isn't obvious to other people. Given as they often do appear to elicit some sort of response from the person undergoing the exorcism, and given that not everyone undergoing an exorcism wants to be undergoing an exorcism (such as those who are homosexual for obvious reasons) one theoretical argument from a scientific perspective could be that the effect of people yelling and screaming at you is enough to elicit an emotional response.

See spirit possession for scientific explanations of alleged spirit possessions in general.

The job of exorcist would seem to be perfect for a psychopathicsadist. They are usually able to get away with anything short of murder: kidnapping, torture and general mayhem. Here are some cases where the psychopaths were caught:

In 1976, one of the most famous exorcism killings occurred: Anneliese Michel was starved and dehydrated to death by parents and priests.[16] Three films were based on true stories this case, The Exorcism of Emily Rose, Requiem, and Anneliese: The Exorcist Tapes.

In 1993 Joan Vollmer died of a heart attack induced by her husband and 2 friends.[30]

In 1976, one of the most famous exorcism killings occurred: Anneliese Michel was starved and dehydrated to death by parents and priests.[16] Three films were based on true stories this case, The Exorcism of Emily Rose, Requiem, and Anneliese: The Exorcist Tapes.

In 1997 Kyung Jae Chung was stomped to death by Jin Hyun Choi under the guise of "anchal prayer".[33]

In 1997 Breeann Spickard was beaten to death by Julia Ann Olivas and Esther Rebecca Griggs.[34]

In 1997 Amy Burney was poisoned to death; her mother Angelee Burney and grandmother Rosa Downing were charged.[35]

In 1997 Chua Wan Zuen was crushed to death by 8 people, including family members.[28]

In 1998 Charity Miranda-Martin was asphyxiated; her mother and daughter were charged with murder.[36]

In 2001 Signifagance Oliver was drowned by her mother, Sabrina Wright.[37]

In 2012 Latifa Hachmi was tortured to death over a period of one month.[29]

In 2014 Norell Harris and Zyana Harris were stabbed to death by their mother, Zakieya L. Avery.[20][22][51]

In 2015, Jaqueline Sanchez died from cardiac arrest during an exorcism in San Ignacio, Bolivia. The victim also had bruising and lacerations.[52]

In 2015, German police arrested 5 unidentified South Korean family members in connection with exorcisms. Two other unidentified South Korean women were found, one dead and the other injured. The victims were bound, gagged and beaten for hours; the survivor was also suffering from hypothermia.[53]

In 2016, Jack Gian Banday, a 5-year old boy, was beaten and strangled to death in the Philippines during an exorcism ritual inside a church by 3 relatives who were later arrested.[54]

In 2017, Vilma Trujillo Garcia was burned to death after being thrown naked into flames during an exorcism ritual in Nicaragua.[55]

In 2018, Juanita Gomez was found guilty of murder her 33-year old daughter in an exorcism attempt by shoving a crucifix down her throat.[56]

In 2018, Vietnamese singer Nguyen Viet Cuong (a.k.a., Chau Viet Cuong) was accused of killing a woman in an exorcism while under the influence of drugs. The woman died from asphyxiation after being force-fed garlic cloves.[57]